MB of anthropogenic origin is, however, estimated to cause between 5 and 10 % of total ozone depletion in the earth's stratosphere. Ozone depletion increases the level of UV-B radiation which has been linked to skin cancer, eye cataracts, and degradation of the immune system. Direct exposure to MB leads to acute and chronic health problems including respiratory difficulties, neurological disorders and even death. In developing countries particular health hazards during application persist in spite of considerable training activities. Possible implications of UV-B radiation on ecosystems include yield reduction in different crops, impacts on forest trees, freshwater, wetland and marine ecosystems. Because of these effects, in the ninth meeting of the parties to the Montreal Protocol (MP) held in September 1997, the phase-out of this fumigant in industrialised countries by the year 2005 was decided. Some countries agreed voluntarily on earlier phase-outs (including Austria, Denmark, Finland, Indonesia, Norway, Sweden and the United States of America - USA). In a number of countries, such as Germany and the Netherlands, specific treatments have already been phased out, partly for toxicological reasons. Many industrialised countries have reduced MB use for commercial, safety or environmental reasons. The phase-out date for developing countries has been fixed for the year 2015. According to the UNEP, eliminating MB is the most significant step to reducing ozone depletion.